Grindstone for grinding wood pulp



kfio

Patented Nov. 21, 1933 UNITED STATES PATENT OFFICE Andreas Jordan,

Application October 30,

and in Germany 7 Claims.

My invention relates to the grinding of wood into the so-called mechanica pulp used in the manufacture of newsprint and other cheap papers, and more particularly to improvements in the grindstones forming part of the mechanical wood pulp grinders.

It is an object of my invention to provide a grindstone, which, when in use, is relieved, as far as possible, of all inner stresses. With this and other objects in view I will now describe my invention more in detail, as applied to a comparatively thin-walled grindstone of annular cross-section, which is secured on the shaft by means of lateral stone anges. Thin-walled grindstones of annular cross-section are known to be superior to solid stones in that they are relatively of light weight, heat up uniformly in operation and are therefore less subjected to inner stresses. The stones of annular cross-section hitherto suggested, while being equipped with spoke-like ribs or the like, did not always offer a sufficient bearing surface to the stone flanges, as is required by the braking resistance exerted on the stone by the wood to be ground.

According to the present invention the grindstone of annular cross-section is provided at its end faces with pressure-resistive inwardly projecting flanges, which take up that part of the clamping pressure, which is not exerted on the solid portion of the stone. These fianges further offer the advantage of narrowing down the central boring at the end faces of the stone in such manner, that the stone can readily be centered on the shaft in a well known manner, i. e. by means of wedges.

The fianges formed near the end faces of the cylindrical stone are preferably formed with substantially triangular cross-section and reinforced by radial ribs extending in parallel to the cylinder axis, circumferential ribs being also provided on the inner wall, if desired.

In the drawing aflixed to this specification and forming part thereof, a grindstone embodying my invention is illustrated diagrammatically by way of example.

In the drawing,

Fig. 1 is an axial section,

Fig. 2 a cross-section.

Referring to the drawing, a is the comparatively thin-walled grindstone of annular crosssection and b, b are flanges formed near the end faces of the hollow cylinder and projecting inwardly and axially outwardly to adapt them to the steel flanges mounted on the shaft of the grinder, which hold the stone between them by clamping action. The flanges b thus project slightly beyond the end faces of the grindstone, forming low conical projections. c are axial ribs, d is a circumferential rib formed on the inner surface of the stone and projecting radially to- Dresden, Germany 1931, Serial No. 572,002, November 15, 1930 wards the middle axis. e and f are reinforcing wires of a well known kind embedded in the stone material and e' are substantially radial extensions of these reinforcing members forming triangular reinforcing elements for the iianges b.

Obviously ribs, such as c and d, might also be dispensed with.

The mounting of a grindstone of this kind on its shaft is effected as usual, the two steel flanges screwed onto the shaft or fixed thereon in any other suitable manner holding the end faces of the stone between them and exerting pressure mainly on the reinforced flanges b, which are thus instrumental in relieving the grindstone proper of most of the clamping pressure.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

In the claims aiiixed to this specification no selection of any particular modification of the invention is intended to the exclusion of other modifications thereof and the right to subsequently make claim to any modification not covered by these claims is expressly reserved.

I claimt- 1. A grindstone for wood pulp grinders comprising a hollow cylindrical comparatively thinwalled stone body, radially inwardly projecting annular flanges formed near the end faces of the cylinder, and metallic reinforcing means in said stone body and in the ange portions.

2. A grindstone for wood pulp grinders comprising a hollow cylindrical comparatively thinwalled stone body, radially inwardly projecting annular fianges of substantially triangular crosssection formed near the end faces of the cylinder, and metallic reinforcing means extending into said flange portions.

3. A grindstone for wood pulp grinders comprising a hollow cylindrical stone body having a central bore of large diameter becoming smaller at both ends, the resulting ange-like portions thereby formed at said ends serving as means for clamping the said body to a shaft.

4. The grindstone of claim 3 wherein the end faces are bulged outwardly in an axial direction and are formed into annular, centrally projecting flanges.

5. The grindstone of claim 3 wherein the said flange-like portions are substantially triangular in cross-section.

6. The grindstone of claim 3 wherein the internal bore is provided with reinforcing ribs.

'7. The grindstone of claim 3 wherein the internal bore is provided with reinforcing ribs running both axially and circumferentially.

ANDREAS JORDAN. 

